up2date -u installs i386 and i586 kernels on athlons. This should be an
athlon kernel. Some drivers make assumptions about how various pci
registers are to be programmed based on the cache line size, which only the
athlon kernel gets correct.
This will be fixed in the next version of up2date to be errata'ed.
Could you put copy of those patches somewhere or one in rawhide (if its not
already there) I'd like to look at that.